/*
 * Copyright (c) JForum Team
 * All rights reserved.
 
 * Redistribution and use in source and binary forms, 
 * with or without modification, are permitted provided 
 * that the following conditions are met:
 
 * 1) Redistributions of source code must retain the above 
 * copyright notice, this list of conditions and the 
 * following  disclaimer.
 * 2)  Redistributions in binary form must reproduce the 
 * above copyright notice, this list of conditions and 
 * the following disclaimer in the documentation and/or 
 * other materials provided with the distribution.
 * 3) Neither the name of "Rafael Steil" nor 
 * the names of its contributors may be used to endorse 
 * or promote products derived from this software without 
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT 
 * HOLDERS AND CONTRIBUTORS "AS IS" AND ANY 
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, 
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 
 * THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE 
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER 
 * IN CONTRACT, STRICT LIABILITY, OR TORT 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE
 * 
 * Created on May 31, 2004 by pieter
 * The JForum Project
 * http://www.jforum.net
 */
package com.binhthuan.catechist.server.util.preferences;

import java.util.HashMap;
import java.util.Map;

/**
 * @author Pieter
 * @author Rafael Steil
 * @version $Id: VariableExpander.java,v 1.6 2006/08/20 22:47:37 rafaelsteil Exp
 *          $
 */
public class VariableExpander {
    private VariableStore variables;

    private String pre;
    private String post;

    private Map<String, String> cache;

    public VariableExpander(VariableStore variables, String pre, String post) {
        this.variables = variables;
        this.pre = pre;
        this.post = post;
        cache = new HashMap<String, String>();
    }

    public void clearCache() {
        cache.clear();
    }

    public String expandVariables(String source) {
        String result = this.cache.get(source);

        if (source == null || result != null) {
            return result;
        }

        int fIndex = source.indexOf(this.pre);

        if (fIndex == -1) {
            return source;
        }

        StringBuffer sb = new StringBuffer(source);

        while (fIndex > -1) {
            int lIndex = sb.indexOf(this.post);

            int start = fIndex + this.pre.length();

            if (fIndex == 0) {
                String varName = sb.substring(start, start + lIndex - this.pre.length());
                sb.replace(fIndex, fIndex + lIndex + 1, this.variables.getVariableValue(varName));
            } else {
                String varName = sb.substring(start, lIndex);
                sb.replace(fIndex, lIndex + 1, this.variables.getVariableValue(varName));
            }

            fIndex = sb.indexOf(this.pre);
        }

        result = sb.toString();

        this.cache.put(source, result);

        return result;
    }
}
